JP2018120747A - Fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the worsening of a power generation performance of a fuel cell stack in which at least one of two separators located on both sides of an electrolyte membrane-electrode assembly is a separator having no cooling medium flow path formed therein.SOLUTION: A fuel cell stack includes: two cooling separators (i.e. a first cooling separator 11 and a second cooling separator 15) with a first electrolyte membrane-electrode assembly 12 and a second electrolyte membrane-electrode assembly 14 interposed therebetween, of which the second cooling separator 15 has a first oxidant gas flow path 32 for supplying an oxidant gas to a second cathode 27; and an intermediate separator 13a having a second oxidant gas flow path 30 for supplying an oxidant gas to a first cathode 21. The second oxidant gas flow path 30 of the intermediate separator 13a is larger, in flow path cross section, than the flow path cross section of the first oxidant gas flow path 32 of the second cooling separator 15. Therefore, the oxidant gas can be supplied to the first oxidant gas flow path 32 and the second oxidant gas flow path 30 uniformly and the worsening of a power generation performance can be suppressed.SELECTED DRAWING: Figure 2

Description

  In the present invention, at least one of the two separators sandwiching the electrolyte membrane-electrode assembly is an intermediate separator in which no cooling medium flow path is formed, and a cooling medium flow path for supplying a cooling medium is formed. The present invention relates to a fuel cell stack in which a plurality of electrolyte membrane-electrode assemblies are interposed between two cooling separators.

  A polymer electrolyte fuel cell has a catalytic reaction layer mainly composed of carbon powder carrying a platinum-based metal catalyst on both main surfaces of an electrolyte membrane, and further has gas permeability and conductivity on the outside. An electrolyte membrane-electrode assembly having an anode and a cathode arranged by arranging a pair of gas diffusion layers.

  Then, by supplying a fuel gas containing hydrogen to the anode of the fuel cell having the above structure and supplying an oxidant gas containing oxygen to the cathode, electric energy can be continuously taken out.

  In order to prevent the fuel gas and the oxidant gas from being mixed, a separator is disposed between each electrolyte membrane-electrode assembly. A cell in which an electrolyte membrane-electrode assembly is sandwiched between a pair of separators is called a cell. A unit structure composed of two or more cells is called a cell module. Necessary electric power can be secured by stacking a plurality of cells or cell modules so as to be electrically in series.

  In the fuel cell stack, a pair of current collecting plates having terminals for connecting to an external circuit and taking out electric power are arranged at both outer ends of a plurality of stacked cells or cell modules, and further, at both outer ends of the current collecting plates. A pair of end plates are arranged.

  Further, since the fuel cell generates heat due to a power generation reaction, it is necessary to cool it by supplying a cooling medium. In general, the fuel cell stack is cooled by forming a cooling medium flow path for supplying a cooling medium to a surface of the separator opposite to the surface in contact with the anode or the cathode.

  Further, a cooling separator in which a fuel gas passage or an oxidant gas passage and a cooling medium passage are formed, an intermediate separator in which a fuel gas passage and an oxidant gas passage are formed and no cooling medium passage is formed, Has been proposed. According to this fuel cell stack, since the number of cooling separators can be reduced, it is possible to reduce the space and cost of the fuel cell stack.

  In addition, as a fuel cell stack having a cooling separator and an intermediate separator, the flow path cross-sectional area of the fuel gas flow path of the intermediate separator is made larger than the flow cross-sectional area of the fuel gas flow path of the cooling separator. A configuration has been proposed (see, for example, Patent Document 1).

  FIG. 5 shows a main cross section of a cell module of a conventional fuel cell stack described in Patent Document 1. As shown in FIG.

  As shown in FIG. 5, the cell module 201 is laminated in the order of a first cooling separator 202, a first electrolyte membrane-electrode assembly 203, an intermediate separator 204, a second electrolyte membrane-electrode assembly 205, and a second cooling separator 206. Configured.

  The first electrolyte membrane-electrode assembly 203 includes a first electrolyte membrane 207, a first anode catalyst layer 208 and a first cathode catalyst layer 209 formed on both surfaces of the first electrolyte membrane 207, and a first anode catalyst layer 208. And a first gas diffusion layer 210 provided at both outer ends of the first cathode catalyst layer 209.

  The first electrolyte membrane-electrode assembly 203 includes a first anode 211 formed by the first anode catalyst layer 208 and the first gas diffusion layer 210 provided outside the first anode catalyst layer 208. A first cathode 212 formed so as to be in contact with one cooling separator 202 and further formed with a first cathode catalyst layer 209 and a first gas diffusion layer 210 provided outside the first cathode catalyst layer 209 includes an intermediate It is provided in contact with the separator 204.

  The second electrolyte membrane-electrode assembly 205 includes a second electrolyte membrane 213, a second anode catalyst layer 214 and a second cathode catalyst layer 215 formed on both surfaces of the second electrolyte membrane 213, and a second anode catalyst layer 214. And a second gas diffusion layer 216 provided at both outer ends of the second cathode catalyst layer 215.

  The second electrolyte membrane-electrode assembly 205 includes a second anode 217 formed by a second anode catalyst layer 214 and a second gas diffusion layer 216 provided outside the second anode catalyst layer 214. A second cathode 218 formed so as to be in contact with the separator 204 and formed of a second cathode catalyst layer 215 and a second gas diffusion layer 216 provided outside the second cathode catalyst layer 215 is further It is provided in contact with the separator 206.

  The first cooling separator 202 has a first fuel gas channel 219 formed on the surface in contact with the first anode 211, and a first cooling medium channel 220 formed on the surface opposite to the surface in contact with the first anode 211. .

  The intermediate separator 204 has a second dioxide gas channel 221 formed on the surface in contact with the first cathode 212 and a second fuel gas channel 222 formed on the surface in contact with the second anode 217. Further, the flow passage cross-sectional area of the second fuel gas flow passage 222 is larger than the flow passage cross-sectional area of the first fuel gas flow passage 219.

  The second cooling separator 206 has a first oxidant gas flow path 223 formed on the surface in contact with the second cathode 218 and a second cooling medium flow path 224 formed on the surface opposite to the surface in contact with the second cathode 218. Has been.

  Although not shown in the drawings, the conventional fuel cell stack is configured by stacking a plurality of cell modules 201, and the first cooling separator 202 and the second cooling separator 206 are in a front-back relationship, so that the first cooling medium A cooling medium flow path is formed by the flow path 220 and the second cooling medium flow path 224.

JP 2010-212216 A

The first cooling separator 202 and the second cooling separator 206 are cooled by the cooling medium flowing through the cooling medium flow path, while the intermediate separator 204 is interposed between the first cooling separator 202 and the first electrolyte membrane-electrode joint. Since the cooling is performed via the body 203, the second cooling separator 206, and the second electrolyte membrane-electrode assembly 205, the temperature of the intermediate separator 204 is higher than the temperatures of the first cooling separator 202 and the second cooling separator 206. Become.

  When the temperature of the intermediate separator 204 becomes higher than the temperature of the first cooling separator 202 and the second cooling separator 206, the temperature is intermediate than the temperature of hydrogen flowing through the first fuel gas flow path 219 formed in the first cooling separator 202. The temperature of hydrogen flowing through the second fuel gas channel 222 formed in the separator 204 is higher.

  Further, the temperature of the air flowing through the first dioxide gas channel 221 formed in the intermediate separator 204 is higher than the temperature of the air flowing through the first oxidizing gas channel 223 formed in the second cooling separator 206. .

  Here, the relationship between gas temperature and gas viscosity will be described. FIG. 6 is a characteristic diagram showing the correlation between gas temperature and gas viscosity.

  As shown in FIG. 6, the viscosity of hydrogen and air has a characteristic of increasing as the temperature rises, and the amount of change in viscosity with respect to the temperature of air is greater than the amount of change in viscosity with respect to the temperature of hydrogen.

  Further, since the pressure loss is proportional to the viscosity, the pressure loss of the first oxidant gas flow path 223 is larger than the increase rate of the pressure loss of the second fuel gas flow path 222 when the pressure loss of the first fuel gas flow path 219 is used as a reference. The increase rate of the pressure loss of the second dioxide agent gas flow path 221 with reference to is larger.

  Since the fluid becomes difficult to flow when the pressure loss becomes high, the fluid is less than the rate of decrease in the amount of hydrogen supplied to the second fuel gas passage 222 when the amount of hydrogen supplied to the first fuel gas passage 219 is used as a reference. The rate of decrease in the amount of air supplied to the second dioxide gas channel 221 with respect to the amount of air supplied to the monoxide gas channel 223 is greater.

  Therefore, in the configuration of Patent Document 1, since the cross-sectional area of the first oxidant gas flow path 223 and the cross-sectional area of the second dioxide gas flow path 221 are the same, the first oxidant gas flow path 223 is supplied. There is a problem that the amount of air supplied to the second dioxide gas channel 221 is smaller than the amount of air to be generated, and the power generation performance is reduced.

  The present invention solves the above-mentioned conventional problems, and even if at least one of the two separators sandwiching the electrolyte membrane-electrode assembly is an intermediate separator in which no cooling medium flow path is formed, power generation performance is reduced. An object of the present invention is to provide a fuel cell stack that can be suppressed.

  In order to solve the conventional problems, a fuel cell stack of the present invention includes an electrolyte membrane-electrode assembly in which an electrolyte membrane is sandwiched between an anode and a cathode, a cooling separator in which a cooling medium flow path through which a cooling medium flows is formed. An intermediate separator in which no cooling medium flow path is formed, at least one of the two separators sandwiching the electrolyte membrane-electrode assembly is an intermediate separator, and a plurality of electrolyte membranes between the two cooling separators A fuel cell stack in which an electrode assembly is interposed, and one of the two cooling separators in which a plurality of electrolyte membranes and electrode assemblies are interposed is for supplying an oxidant gas to the cathode A first oxidant gas flow path, the intermediate separator has a second oxidant gas flow path for supplying oxidant gas to the cathode, and a cross section of the second oxidant gas flow path But it is larger than the flow path cross-sectional area of the first oxidizing gas channel.

In this way, even if the temperature of the oxidant gas flowing through the first oxidant gas flow path is higher than the temperature of the oxidant gas flowing through the first oxidant gas flow path, the pressure loss of the first oxidant gas flow path is increased. Therefore, it is possible to supply the oxidant gas uniformly to the first oxidant gas flow path and the second oxidant gas flow path.

  In the fuel cell stack of the present invention, at least one of two separators sandwiching an electrolyte membrane-electrode assembly is an intermediate separator, and a plurality of electrolyte membrane-electrode assemblies are interposed between two cooling separators. Even in the stack, it is possible to suppress a decrease in power generation performance and maintain good power generation performance.

1 is a perspective view of a fuel cell stack according to Embodiment 1 of the present invention. 1 is a cross-sectional view of a cell module when the fuel cell stack according to Embodiment 1 of the present invention is cut along line II in FIG. The perspective view of the fuel cell stack in Embodiment 2 of this invention Cell module sectional view when the fuel cell stack according to Embodiment 2 of the present invention is cut along line II-II in FIG. Main sectional view of a conventional cell module of a fuel cell stack Characteristic diagram showing correlation between gas temperature and gas viscosity

  The first invention includes an electrolyte membrane-electrode assembly in which an electrolyte membrane is sandwiched between an anode and a cathode, a cooling separator in which a cooling medium flow path through which a cooling medium flows is formed, and an intermediate in which no cooling medium flow path is formed. A fuel cell stack in which at least one of the two separators sandwiching the electrolyte membrane-electrode assembly is an intermediate separator and a plurality of electrolyte membrane-electrode assemblies are interposed between the two cooling separators. One of the two cooling separators having a plurality of electrolyte membrane-electrode assemblies interposed therebetween has a first oxidant gas flow path for supplying oxidant gas to the cathode. The intermediate separator has a second dioxide gas channel for supplying the oxidant gas to the cathode, and the sectional area of the first oxidant gas channel is the sectional area of the first oxidant gas channel. Greater than It is have a fuel cell stack.

  With the above configuration, even if the temperature of the oxidant gas flowing through the second dioxide gas channel is higher than the temperature of the oxidant gas flowing through the first oxidant gas channel, Since the cross-sectional area of the first dioxide gas flow path is larger than the cross-sectional area of the road, it is possible to prevent an increase in pressure loss of the second dioxide gas flow path and to equalize the pressure loss of the first oxidant gas flow path.

  By doing so, it becomes possible to supply the oxidant gas uniformly to the first oxidant gas flow path and the second dioxide gas flow path, and at least one of the two separators sandwiching the electrolyte membrane-electrode assembly is intermediate. Even in a fuel cell stack that is a separator and in which a plurality of electrolyte membrane-electrode assemblies are interposed between two cooling separators, good power generation performance can be maintained while suppressing a decrease in power generation performance.

  According to a second aspect of the invention, in the first aspect of the invention, the other cooling separator of the two cooling separators having a plurality of electrolyte membrane-electrode assemblies interposed therebetween supplies the fuel gas to the anode. A first fuel gas flow path, the intermediate separator has a second fuel gas flow path for supplying fuel gas to the anode, and the cross-sectional area of the second fuel gas flow path is defined as the first fuel gas flow path; It is larger than the channel cross-sectional area of the channel.

  With the above configuration, even if the temperature of the oxidant gas flowing through the second dioxide gas channel is higher than the temperature of the oxidant gas flowing through the first oxidant gas channel, Since the cross-sectional area of the first dioxide gas flow path is larger than the cross-sectional area of the road, it is possible to prevent an increase in pressure loss of the second dioxide gas flow path and to equalize the pressure loss of the first oxidant gas flow path.

  Furthermore, even if the temperature of the fuel gas flowing through the second fuel gas flow path is higher than the temperature of the fuel gas flowing through the first fuel gas flow path, Since the cross-sectional area of the two fuel gas passages is larger, an increase in the pressure loss of the second fuel gas passage can be prevented and the pressure loss of the first fuel gas passage can be made equal.

  By doing so, it becomes possible to supply the oxidant gas uniformly to the first oxidant gas flow path and the second dioxide gas flow path, and to the first fuel gas flow path and the second fuel gas flow path uniformly. It is possible to supply fuel gas, and at least one of the two separators sandwiching the electrolyte membrane-electrode assembly is an intermediate separator, and a plurality of electrolyte membrane-electrode assemblies are interposed between the two cooling separators. Even in the fuel cell stack, it is possible to reliably suppress a decrease in power generation performance and maintain good power generation performance.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the present embodiment.

(Embodiment 1)
FIG. 1 is a perspective view of a fuel cell stack according to Embodiment 1 of the present invention. 2 is a cross-sectional view of the cell module when the fuel cell stack according to Embodiment 1 of the present invention is cut along the line II in FIG.

  As shown in FIG. 1, a fuel cell stack 101A according to the first embodiment includes a current collecting plate 2a including a takeout terminal 3 for connecting to an external current cable at both outer ends of a plurality of stacked cell modules 1a, Insulating plate 2b, current collector plate 2a, end plate 4a provided on both outer sides of current collector plate 2b, end plate 4b, fuel gas supply pipe 5 connected to end plate 4a, cooling The medium supply pipe 6, the oxidant gas supply pipe 7, the fuel gas discharge pipe 8, the cooling medium discharge pipe 9 and the oxidant gas discharge pipe 10 are configured.

  As shown in FIG. 2, the cell module 1a in Embodiment 1 includes a first cooling separator 11, a first electrolyte membrane-electrode assembly 12, an intermediate separator 13a, a second electrolyte membrane-electrode assembly 14, and a second cooling. The separators 15 are stacked in this order.

  The first electrolyte membrane-electrode assembly 12 includes a first electrolyte membrane 16, a first anode catalyst layer 17 and a first cathode catalyst layer 18 formed on both surfaces of the first electrolyte membrane 16, and a first anode catalyst layer 17. And a first gas diffusion layer 19 provided at both outer ends of the first cathode catalyst layer 18.

  The first electrolyte membrane-electrode assembly 12 includes a first anode 20 formed by a first anode catalyst layer 17 and a first gas diffusion layer 19 provided outside the first anode catalyst layer 17. A first cathode 21 formed so as to be in contact with one cooling separator 11 and further formed with a first cathode catalyst layer 18 and a first gas diffusion layer 19 provided outside the first cathode catalyst layer 18 includes an intermediate It is provided in contact with the separator 13a.

  The second electrolyte membrane-electrode assembly 14 includes a second electrolyte membrane 22, a second anode catalyst layer 23 and a second cathode catalyst layer 24 formed on the second electrolyte membrane 22, a second anode catalyst layer 23, and a second anode catalyst layer 23. And a second gas diffusion layer 25 provided at both outer ends of the two-cathode catalyst layer 24.

The second electrolyte membrane-electrode assembly 14 includes a second anode 26 formed by a second anode catalyst layer 23 and a second gas diffusion layer 25 provided outside the second anode catalyst layer 23. A second cathode 27 formed so as to be in contact with the separator 13 a and further formed by the second cathode catalyst layer 24 and the second gas diffusion layer 25 provided outside the second cathode catalyst layer 24 is provided with the second cooling. It is provided in contact with the separator 15.

  In the first cooling separator 11, a first fuel gas channel 28 is formed on the surface in contact with the first anode 20, and a first cooling medium channel 29 is formed on the surface opposite to the surface in contact with the first anode 20. In the second cooling separator 15, a first oxidant gas flow path 32 is formed on the surface in contact with the second cathode 27, and a second cooling medium flow path 34 is formed on the surface opposite to the surface in contact with the second cathode 27. .

  The intermediate separator 13a has a second dioxide gas channel 30 formed on the surface in contact with the first cathode 21 and a second fuel gas channel 31a formed on the surface in contact with the second anode 26.

  The cross-sectional area of the first dioxide gas channel 30 is larger than the cross-sectional area of the first oxidant gas channel 32, and the cross-sectional area of the first dioxide gas channel 30 is The cross-sectional area of the monoxide gas channel 32 is 1.2 times.

  A gasket 33 having gas sealing properties is disposed between the first cooling separator 11, the intermediate separator 13a, and the first electrolyte membrane-electrode assembly 12, and further, the second cooling separator 15, the intermediate separator 13a, and the second electrolyte. It arrange | positions between the membrane-electrode assemblies 14.

  Although not shown, since the fuel cell stack 101A is configured by stacking a plurality of cell modules 1a, the first cooling separator 11 and the second cooling separator 15 are in a front-back relationship, and the first cooling medium flow path 29 and A cooling medium flow path is formed by the second cooling medium flow path 34.

  The current collector plate 2a and the current collector plate 2b are members having appropriate mechanical strength and conductivity. In the present embodiment, copper plated with gold is used. The end plate 4a and the end plate 4b are members having electrical insulation and appropriate mechanical strength. In this embodiment, a polyphenylene sulfide resin that is a thermoplastic resin is used.

  The first cooling separator 11, the second cooling separator 15, and the intermediate separator 13a are members having appropriate mechanical strength and conductivity. In this embodiment, a member formed by heat molding a kneaded product of graphite powder and a thermosetting resin is used.

  The first electrolyte membrane 16 and the second electrolyte membrane 22 are polymer electrolyte membranes having hydrogen ion conductivity. In this embodiment, a fluorine-based polymer electrolyte membrane (Nafion (registered trademark) manufactured by DuPont, USA) made of perfluorocarbon sulfonic acid is used.

  The first gas diffusion layer 19 and the second gas diffusion layer 25 are porous members having conductivity and water repellency. In the present embodiment, PTFE (polytetrafluoroethylene), which is a water-repellent polymer resin typified by a fluororesin, is dispersed in a conductive substrate having a porous structure manufactured using carbon paper. Use constructed members.

  The first anode 20 and the second anode 26 are layers containing a catalyst for hydrogen oxidation reaction. The first cathode 21 and the second cathode 27 are layers containing a catalyst for oxygen reduction reaction. In the present embodiment, a porous member mainly composed of carbon powder carrying a platinum-based metal catalyst and a polymer material having proton conductivity is used.

  The gasket 33 is a synthetic resin having appropriate mechanical strength and flexibility. In this embodiment, fluororubber is used.

  The operation and action of the fuel cell stack 101A configured as described above will be described below.

  First, since the temperature of the intermediate separator 13 a is higher than the temperature of the second cooling separator 15, the oxidant flowing in the second dioxide gas channel 30 than the temperature of the oxidant gas flowing in the first oxidant gas channel 32. The gas temperature is higher.

  Here, since the cell module 1 a has a larger channel cross-sectional area of the first oxidant gas flow channel 30 than a flow channel cross-sectional area of the first oxidant gas flow channel 32, the pressure loss of the first oxidant gas flow channel 30. And the pressure loss of the first oxidant gas flow path 32 can be made equal.

  By doing so, it becomes possible to supply the oxidant gas uniformly to the first oxidant gas flow path 32 and the second dioxide gas flow path 30, and the electrolyte membrane-electrode assembly (first electrolyte membrane-electrode assembly). 12 and the second electrolyte membrane-electrode assembly 14), at least one of the two separators is an intermediate separator 13a, and a plurality of separators are provided between the two cooling separators (the first cooling separator 11 and the second cooling separator 15). Even in the fuel cell stack 101A in which the electrolyte membrane-electrode assembly (the first electrolyte membrane-electrode assembly 12 and the second electrolyte membrane-electrode assembly 14) is interposed, the power generation performance is prevented from being deteriorated and good power generation is achieved. The performance can be maintained.

  In the present embodiment, a cooling medium flow path is formed by the first cooling medium flow path 29 formed in the first cooling separator 11 and the second cooling medium flow path 34 formed in the second cooling separator 15. However, a separator in which the first cooling separator 11 and the second cooling separator 15 are integrally molded may be used, and a cooling medium flow path may be formed inside the integrally molded separator.

  Moreover, although the member formed by heat-molding the kneaded material of graphite powder and a thermosetting resin was used for the 1st cooling separator 11, the 2nd cooling separator 15, and the intermediate separator 13a, in addition to this, carbon powder A metal material can be used by applying gold plating to the surface of a member formed by heat-molding a kneaded product of heat and heat-sparing resin or a plate made of titanium or stainless steel.

  As the first electrolyte membrane 16 and the second electrolyte membrane 22, a fluorine-based polymer electrolyte membrane made of perfluorocarbon sulfonic acid having hydrogen ion conductivity was used, but in addition to this, Aciplex manufactured by Asahi Kasei Co., Ltd. (Registered Trademark), Flemion (Registered Trademark) manufactured by Asahi Glass Co., Ltd.) and various hydrocarbon electrolyte membranes can be used.

  The first gas diffusion layer 19 and the second gas diffusion layer 25 are made of PTFE, which is a water-repellent polymer resin typified by fluororesin, on a conductive base material made of carbon paper and having a porous structure. Although the member comprised by disperse | distributing (polytetrafluoroethylene) was used, besides this, as a conductive base material, carbon fine powder, carbon cloth, etc. can be used.

  The first anode 20, the second anode 26, the first cathode 21, and the second cathode 27 are porous materials mainly composed of carbon powder carrying a platinum-based metal catalyst and a polymer material having proton conductivity. In addition to this, the first anode 20 and the second anode 26 can be used as long as they have conductivity and have a catalytic ability for the oxidation reaction of hydrogen. The cathode 21 and the second cathode 27 can be used as long as they have conductivity and have a catalytic ability for a reduction reaction of oxygen.

  Fluororubber is used for the gasket 33, but other thermoplastic elastomers such as silicone rubber, natural rubber, EPDM, butyl rubber, butyl rubber, polystyrene, polyolefin, polyester and polyamide can be used. .

(Embodiment 2)
FIG. 3 is a perspective view of the fuel cell stack according to Embodiment 2 of the present invention. 4 is a cross-sectional view of the cell module when the fuel cell stack according to Embodiment 2 of the present invention is cut along the line II-II in FIG. In the fuel cell stack according to the second embodiment shown in FIGS. 3 and 4, the same components as those of the fuel cell stack according to the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description thereof is omitted. To do.

  As shown in FIG. 3, the fuel cell stack 101B in the second embodiment is configured by stacking a plurality of cell modules 1b.

  As shown in FIG. 4, the cell module 1b according to the second embodiment includes a first cooling separator 11, a first electrolyte membrane-electrode assembly 12, an intermediate separator 13b, a second electrolyte membrane-electrode assembly 14, and a second cooling. The separators 15 are stacked in this order.

  The first electrolyte membrane-electrode assembly 12 includes a first anode 20 formed by a first anode catalyst layer 17 and a first gas diffusion layer 19 provided outside the first anode catalyst layer 17. The first cathode 21 formed so as to be in contact with the separator 11 and further formed of the first cathode catalyst layer 18 and the first gas diffusion layer 19 provided outside the first cathode catalyst layer 18 includes an intermediate separator 13b. It is provided so that it may touch.

  The second electrolyte membrane-electrode assembly 14 includes a second anode 26 formed by a second anode catalyst layer 23 and a second gas diffusion layer 25 provided outside the second anode catalyst layer 23. It is provided in contact with the separator 13b.

  The intermediate separator 13 b has a second fuel gas flow path 31 b formed on the surface in contact with the second anode 26. Further, the flow passage cross-sectional area of the second fuel gas flow passage 31b is configured to be larger than the flow passage cross-sectional area of the first fuel gas flow passage 28, and the flow passage cross-sectional area of the second fuel gas flow passage 31b is It is 1.1 times the cross-sectional area of one fuel gas flow path 28.

  The operation and action of the fuel cell stack 101B configured as described above will be described below.

  First, since the temperature of the intermediate separator 13 b is higher than the temperature of the second cooling separator 15, the oxidant flowing in the second dioxide gas channel 30 than the temperature of the oxidant gas flowing in the first oxidant gas channel 32. The gas temperature is higher.

  Here, since the cell module 1b has a larger cross-sectional area of the first oxidant gas flow path 30 than a cross-sectional area of the first oxidant gas flow path 32, the pressure loss of the second oxidant gas flow path 30 is larger. And the pressure loss of the first oxidant gas flow path 32 can be made equal.

  Further, since the temperature of the intermediate separator 13 b is higher than the temperature of the first cooling separator 11, the temperature of the fuel gas flowing through the second fuel gas channel 31 b is higher than the temperature of the fuel gas flowing through the first fuel gas channel 28. Is higher.

  Here, in the cell module 1b, the flow passage cross-sectional area of the second fuel gas flow passage 31b is larger than the flow passage cross-sectional area of the first fuel gas flow passage 28. The increase can be prevented and equal to the pressure loss of the first fuel gas flow path 28.

By doing so, it becomes possible to supply the oxidant gas uniformly to the first oxidant gas flow path 32 and the second dioxide gas flow path 30, and the first fuel gas flow path 28 and the second fuel gas flow The fuel gas can be uniformly supplied to the passage 31b, and at least two separators sandwiching the electrolyte membrane-electrode assembly (the first electrolyte membrane-electrode assembly 12 and the second electrolyte membrane-electrode assembly 14) are provided. One is an intermediate separator 13b, and a plurality of electrolyte membrane-electrode assemblies (the first electrolyte membrane-electrode assembly 12 and the second one) are provided between two cooling separators (the first cooling separator 11 and the second cooling separator 15). Even in the fuel cell stack 101B in which the electrolyte membrane-electrode assembly 14) is interposed, it is possible to reliably suppress a decrease in power generation performance and maintain good power generation performance.

  As described above, in the fuel cell stack according to the present invention, at least one of the two separators sandwiching the electrolyte membrane-electrode assembly is an intermediate separator, and a plurality of electrolyte membrane-electrodes are provided between the two cooling separators. Even in a configuration with a joined body, it is possible to maintain good power generation performance by suppressing power generation performance degradation, so portable power supplies, power supplies for portable devices, power supplies for electric vehicles, home cogeneration systems It can also be applied to other uses.

DESCRIPTION OF SYMBOLS 1a, 1b Cell module 2a, 2b Current collector plate 3 Extraction terminal 4a, 4b End plate 5 Fuel gas supply piping 6 Coolant supply piping 7 Oxidant gas supply piping 8 Fuel gas discharge piping 9 Cooling medium discharge piping 10 Oxidant gas discharge Pipe 11 First cooling separator 12 First electrolyte membrane-electrode assembly 13a, 13b Intermediate separator 14 Second electrolyte membrane-electrode assembly 15 Second cooling separator 16 First electrolyte membrane 17 First anode catalyst layer 18 First cathode catalyst Layer 19 First gas diffusion layer 20 First anode 21 First cathode 22 Second electrolyte membrane 23 Second anode catalyst layer 24 Second cathode catalyst layer 25 Second gas diffusion layer 26 Second anode 27 Second cathode 28 First fuel Gas flow path 29 First cooling medium flow path 30 Second dioxide gas flow path 31a, 31b Second fuel gas flow path 3 The first oxidant gas passage 33 Gasket 34 second cooling medium channel 101A, 101B fuel cell stack

Claims (2)

An electrolyte membrane-electrode assembly in which an electrolyte membrane is sandwiched between an anode and a cathode, a cooling separator in which a cooling medium flow path through which a cooling medium flows is formed, and an intermediate separator in which the cooling medium flow path is not formed ,
A fuel cell stack in which at least one of two separators sandwiching the electrolyte membrane-electrode assembly is the intermediate separator, and a plurality of the electrolyte membrane-electrode assemblies are interposed between the two cooling separators. ,
One cooling separator of the two cooling separators having a plurality of the electrolyte membrane-electrode assemblies interposed therebetween has a first oxidant gas flow path for supplying an oxidant gas to the cathode. The intermediate separator has a second dioxide gas channel for supplying an oxidant gas to the cathode, and a cross-sectional area of the first dioxide gas channel is the first oxidant gas flow. A fuel cell stack that is larger than the cross-sectional area of the channel. The other cooling separator of the two cooling separators having a plurality of the electrolyte membrane-electrode assemblies interposed therebetween has a first fuel gas flow path for supplying fuel gas to the anode. The intermediate separator has a second fuel gas channel for supplying fuel gas to the anode, and a channel cross-sectional area of the second fuel gas channel is a channel of the first fuel gas channel. The fuel cell stack according to claim 1, wherein the fuel cell stack is larger than a cross-sectional area.

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